CLIMATE: HOW WHERE YOU LIVE AFFECTS WHAT YOU GROW

Plants, like people, have definite ideas about where they like to live. Like people, they flourish in congenial conditions and become weak and dispirited if life is
too difficult for them to cope with. Unlike people, however, plants can't take practical steps to improve their homesite — they can't up and move,
and they can't protect themselves against adverse conditions. You, the gardener, are largely responsible for how well your plants do in the climatic
conditions you offer them, and you'll save yourself a lot of frustration and disappointment if you have some understanding of how climate affects your
garden and if you choose your crops according your climate.
What gardeners mean by a "growing season" Throughout this book you'll encounter references to the "growing season." The growing season is,
essentially, the length of time your area can give plants the conditions they need to reach maturity and produce a crop. The growing season is measured in
terms of the number of days between the last frost in spring and the first frost in fall. In general terms. these two dates mark the beginning and end of the
time in which plants grow from seed to maturity. Some areas never have frost at all and use their dry season as their "winter." In these areas, however,
it's still possible to use hypothetical "frost" dates. So the length of your growing season is (technically) totally dependent on your local climate. When you
plant a vegetable depends on how well that vegetable handles extremes of temperature.
The dates on which a certain area can expect to have the last spring frost and the first fall frost are called the "average date of last frost" and the "average date of first frost," respectively. They are generally used as reference points for planning and planting vegetables, but they're not infallible. They do however, give you a fairly accurate guide as to which vegetables will do best in your area, and they
are the reference points most generally used in this book. As with every other aspect of gardening you need to be a little bit flexible. The chart at the end of
this chapter lists the average dates of first and last frosts in major cities throughout the United States. If you live within 10 miles of a city listed, you can
take these dates as accurate; three or four days either way is just as acceptable, so don't feel you must do all your planting exactly on the one listed day. All these
dates are average, and the weather can always spring surprises. If you live a long way from a listed city or are for any reason unsure when to plant, call your
local Cooperative Extension Service or Weather Bureau for advice. The Cooperative Extension Service is a joint effort of the United States
Department of Agriculture and the state land-grant colleges and universities. The service's local office is an invaluable resource for the gardener, and a list of
offices throughout the country appears in Part 4. Climatic or "hardiness" zones
The average date of last frost is not the only reference point used to determine when to plant a garden. At one time or other gardeners have made
that date dependent on everything from "climatic zones" to the phases of the moon. Climatic zones are the small maps you find on the back of seed
packages; they divide the United States into zones or areas with fairly similar climates. They're probably far more accurate references for planting than
phases of the moon, but they're very general, and they don't tell the whole story. There are many incidental — sometimes almost accidental —conditions that can cause changes in climate within a climatic zone.
The climatic zone map in the seed catalog or on the back of a seed packet can give you a broad idea of how a vegetable (or vegetable variety, because carrots, tomatoes, and other popular vegetables don't by any means conform to a stereotype) will do in your area. Climatic zones, however, don't take into
account the variations that occur within an area which, if you go by the book, has the same climatic conditions prevailing over many square miles. For
instance, if the balcony of your downtown apartment faces south, you may be able to grow vegetables on it that would never survive in a north-facing garden of
your apartment block. Lots of large buildings, a nearby body of water like a lake, or even heavy traffic can significantly alter the temperature (and pollution level) in a small garden. So, given all these imponderables, it's safer to judge how well a
vegetable will grow by considering its own tolerance to certain conditions, rather than by a hard-and-fast map reference.
How 'hardiness'' affects your garden plan The way a vegetable type reacts to climatic conditions — heat, cold, moisture, and soon — determines its "hardiness." It's another way of saying how tough it is, but the term hardiness is
used specifically to indicate how well a plant tolerates cold. Before you study how climate affects your garden, it's as well to consider which hardiness categories certain vegetables fall into. The hardiness of each kind determines how that
particular vegetable will fit into your growing season.
The vegetables that are grown in a home vegetable garden fall into one of four hardiness categories: very hardy, hardy, tender, and very tender. The date on which you can safely plant each vegetable in your garden depends on which
hardiness category it falls into.
Very hardy vegetables can tolerate cold and frost and can be planted in the garden four to six weeks before the average date of last frost. They include
asparagus, broccoli, Brussels sprouts, cabbage, cauliflower, collards, Chinese cabbage, horseradish, Jerusalem artichokes, kale, kohlrabi, leeks, lettuce, onions, peas, rhubarb, rutabagas, and shallots; and the herbs chives, garlic, mint,
tarragon and thyme.
Hardy vegetables can handle a certain amount of cold and frost and can be planted two to three weeks before the average date of last frost. They include
beets, cardoon, carrots, celeriac, celery, chard, chicory, dandelion, endive, parsnips, Irish potatoes, radishes, salsify, turnips; and the herbs
anise, borage, fennel, marjoram, oregano, parsley, rosemary, and savory.
Tender vegetables don't like cold weather and can be planted on the average date of last frost; you will need to protect them in some way if there's a late
frost. These vegetables include most beans, cress, mustard, sorrel, corn, tomatoes; the perennial artichokes; and the herbs basil, caraway, chervil, coriander, dill, sage, and sesame. Very tender vegetables will not survive any frost
and must be planted after the soil has warmed up in the spring; they can be planted two to three weeks after the average date of last frost. These vegetables
include lima beans, cucumbers, eggplant, muskmelons, okra, peanuts, peppers, pumpkins, winter and summer squash, and watermelons. Gamblers can take a chance and plant earlier than these dates, but usually this gambling will not pay off. Even if you beat the odds and your plants are not frozen out, they will probably be inhibited by the cold soil, and they won't grow any faster than they would if you planted them at the proper time.